The food service industry serves numerous, freshly mixed soft drinks to customers each day. For various reasons, the industry desires to create the soft drinks for the customer after the customer places an order for the drink. To create the soft drinks, the server mixes soda or carbonated water (hereinafter referred to as soda) with the flavoring syrup of the customer's choice. The industry desires to create drinks in this manner as fast as possible while maintaining the highest quality product.
In order to create a soft drink quickly, the required volumes of soda and syrup must be dispensed into the target container at a high flow rate. Dispensing soda at a high flow rate often leads to foaming. Soda is generally effervescent when not under pressure. The presence of effervescence in soft drinks is desirable when the soft drink is served to the customer. A soft drink that lacks effervescence is commonly referred to as being a "flat" drink. Effervescence is caused by gas escaping from the soda and is increased by agitating the soda. A major problem, therefore, with dispensing soda quickly is controlling rapid effervescence because rapid effervescence causes foam. Foam is undesirable to the soft drink creation process because the server must wait until the foam recedes until filling the remaining section of the target container. Foam is also undesirable because foaming results in soft drinks that are "flat". Foaming also causes spills that make the outside of the target container wet and increase clean-up time.
To reduce foaming problems, the soda is dispensed in a "soft" flow. A "soft" flow is one that is as undisturbed as possible, thus minimizing the agitation that increases effervescence. Preferably, the soda flow is only accelerated by the force of gravity as it falls into the target container.
A problem with creating a soft drink using a "soft" flow of soda occurs when the syrup is mixed with the soda. The degree of mixing generally increases with increased agitation. But for the reasons described above, soda cannot be agitated without causing foaming. Thus, another major problem with quickly creating a soft drink is adequately mixing the syrup with the soda without causing foaming. An inadequately mixed soft drink contains sweet spots where the syrup concentration is higher and than in other areas of the drink. This is typically referred to as stratification of the soft drink.
Numerous types of soft drink dispensing heads are known to the art. One type of dispensing head teaches that the syrup and soda be mixed in the dispensing head by means of a mechanical diffuser and then dropped into the target container. Soft drink dispensers of this nature have been typically slow in operation due to the foaming action which results when the syrup and soda are mixed, particularly at fast flow rates. The joining of the syrup with the soda within the dispensing head causes foam to be generated in the head itself such that foam rather than liquid is dispensed. As a result, dispensing the drink must be done in steps with intermittent pauses introduced by the operator to allow the foam to settle. Such pauses delay the dispensing operation and, in a fast service environment, become extremely costly.
Another known beverage dispensing head operates to reduce foaming by dispensing a "soft" flow of soda separate from a stream of syrup. The soda and the syrup mix when they collide with ice normally present in the target container. Such an operation reduces foaming because the soda is not agitated until it reaches the target container. Furthermore, it is well known in the art that foaming decreases as temperature decreases. Thus, the ice in the target container also serves to decrease foaming. Another technique which may be employed to reduce foaming is to dispense the syrup at a low temperature, thus slowing the mixing time with the soda. Although foaming is reduced, thorough mixing is often not achieved with such dispensing techniques.